Math Problem Statement

Solve the following system of equations: 1. (1/4)x - 2y = -3/4 2. (1/5)x + (1/2)y = 12

Solution

The system of equations given in the image is:

14x2y=34\frac{1}{4}x - 2y = -\frac{3}{4} 15x+12y=12\frac{1}{5}x + \frac{1}{2}y = 12

Step 1: Clear the Fractions

To make the equations easier to work with, let's clear the fractions by multiplying each equation by the least common multiple (LCM) of the denominators.

For the first equation:

  • The LCM of 4 is 4.

Multiply the entire first equation by 4:

4(14x)4(2y)=4(34)4 \left(\frac{1}{4}x\right) - 4(2y) = 4\left(-\frac{3}{4}\right) x8y=3(Equation 1)x - 8y = -3 \quad \text{(Equation 1)}

For the second equation:

  • The LCM of 5 and 2 is 10.

Multiply the entire second equation by 10:

10(15x)+10(12y)=10(12)10\left(\frac{1}{5}x\right) + 10\left(\frac{1}{2}y\right) = 10(12) 2x+5y=120(Equation 2)2x + 5y = 120 \quad \text{(Equation 2)}

Step 2: Solve the System

Now, solve the system of equations:

  1. x8y=3x - 8y = -3
  2. 2x+5y=1202x + 5y = 120

Let's solve by substitution or elimination. We will use the elimination method.

Multiply the first equation by 2:

2(x8y)=2(3)2(x - 8y) = 2(-3) 2x16y=6(Equation 3)2x - 16y = -6 \quad \text{(Equation 3)}

Now, subtract Equation 3 from Equation 2: (2x+5y)(2x16y)=120(6)(2x + 5y) - (2x - 16y) = 120 - (-6) 21y=12621y = 126 y=12621=6y = \frac{126}{21} = 6

Substitute y=6y = 6 into Equation 1:

x8(6)=3x - 8(6) = -3 x48=3x - 48 = -3 x=3+48=45x = -3 + 48 = 45

Solution

The solution to the system is: x=45,y=6x = 45, \quad y = 6

Would you like any additional details, or do you have any questions?

Related Questions:

  1. What would happen if you solved the system using the substitution method instead?
  2. How can you check if the solution x=45x = 45 and y=6y = 6 is correct?
  3. Can you express the second equation in terms of yy and then substitute?
  4. What does it mean geometrically to solve a system of linear equations?
  5. How would you approach this problem if the equations were nonlinear?

Tip:

When dealing with fractions in equations, it's often helpful to clear them out by multiplying through by the least common multiple of the denominators before solving the system.

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Math Problem Analysis

Mathematical Concepts

Algebra
Linear Equations
Systems of Equations
Elimination Method

Formulas

Clearing fractions by multiplying by the least common multiple
Substitution and elimination methods for solving systems of equations

Theorems

No specific named theorems; involves fundamental properties of linear equations

Suitable Grade Level

Grades 9-12